This invention relates to the general field of controlling insect pests with chemical agents and in particular to the spot treatment of animals with an insect growth regulator.
Parasitic infestation by fleas, ticks and the like of domestic animals, such as dogs and cats, results in considerable nuisance, pain and possible harm to the infested animals as well as the animals'owners. Such infestation also results in the transmission of disease to and between humans and domestic animals. For this reason effective control of such parasites has always been desirable and necessary.
Adult fleas generally live in the coat and surrounding environment of the host animal. They feed on the host's blood and lay their eggs in the host's coat. Many of the flea eggs do not stick to the animal, because they are not glued to the coat or skin, and so the eggs fall off the animal into the surrounding environment. Insecticides applied to the animal will generally kill the adult fleas on the animal, but are not generally effective in killing the egg or pupated stages of the fleas because these stages are not normally on the animal. Except where an insecticide has an extremely long effective or residual life, use of such insecticides generally does not prevent re-infestation at the time when the eggs released by fleas prior to or during treatment subsequently hatch, mature through a pupa stage and return to the animal as adults.
Active compounds which inhibit the growth of parasites, such as fleas, have been developed and are applied to the host animal. It is believed by applicants that these compounds either contaminate the eggs or are incorporated into the eggs and thereby effect growth of the eggs and pupae and also thereby prevent eggs and pupated stages of the parasites from developing into adults. In this manner the fleas are prevented from subsequently breeding and re-infestation. Pyriproxyfen or 2-1-methyl-2-(4-phenoxyphenoxy) ethoxy pyridine is a known insect growth regulator, as are insect growth regulators (IGRs) such as lufenuron, diflubenzuron, methoprene and fenoxycarb. U.S. Pat. No. 5,266,324 discloses use of pyriproxyfen in collars for domesticated animals. Applicant understands that formulations containing pyriproxyfen at concentrations of approximately 0.125% by weight have been applied to dogs and cats as a whole body spray or dip to prevent the hatching or maturation of flea eggs and larvae.
Application methods other than collars are desirable because many pet owners consider the collars unsightly and ineffective. Further, such collars often annoy the pets to which they are secured. Application of the active compound through dips or sprays is often undesirable in that such treatments, particularly dips, are difficult to administer and often result in considerable stress to the treated animals. Further, such applications require relatively large amounts of solvent and in the case of dips often result in the waste of considerable excess material.